The core narrative of the film portrays the last months in the life of Serge Alexandre (Stavisky), from late 1933 to January 1934. We see glimpses of his operations as a "financial consultant", setting up a mysterious company to deal in international bonds, his 'laundering' of stolen jewellery, and his juggling of funds to stave off the discovery of fraudulent bonds that he has sold through the Crdit Municipal in Bayonne (municipal pawnbrokers); we see his activity as a theatre impresario in Paris, his casino gambling, his purchase of influence among the press, the police, and politicians, and always his extravagant lifestyle and desire to impress; we see his devotion to his glamorous wife Arlette, his exploitation of her beauty to lure funds from a Spanish revolutionary fascist, his contradictory accounts to his friends of events in his own past, and gleams of political idealism - which may yet be just expedients to create further webs of deception.
Interposed in the narrative are moments of flashback (to his teenage awakening to a hedonistic life, to his arrest as the petty crook Stavisky in 1926, and to his father's suicide after this family dishonour) and flash-forwards (to his funeral, and to the parliamentary enquiry into the Stavisky affair at which his friends and associates testify with varying degrees of honesty).
Also punctuating the main story are scenes depicting the arrival of Trotsky in France to seek political asylum, and his sojourn in various country houses and hotels, receiving visits from left-wing activists. These scenes appear to have no link with the main narrative (apart from two minor characters: the young German-Jewish actress who moves between both stories, and the police-inspector who monitors Trotsky's movements and then also investigates Alexandre), until the end of the film when, in the wake of Stavisky's fall and exposure as a Ukrainian immigrant, a Jew, and a confidant of members of the left-of-centre government, Trotsky's presence is deemed undesirable and he is expelled from the country, while a new 'government of national unity' is formed.
The death of Alexandre/Stavisky in a chalet in Chamonix becomes a further mystery: either a suicide by gunshot, like that of his father, or an assassination by the security forces to ensure his silence.